SOAL
1) All of the following may function in signal transduction in plants except
1) All of the following may function in signal transduction in plants except
A) calcium ions.
B) nonrandom mutations.
C) receptor proteins.
D) phytochrome.
E) secondary messengers.
Answer: B
2) External stimuli would be received most quickly by a
plant cell if the receptors for signal transduction were located in the
A) plasma membrane.
B) cytoplasmic matrix.
C) endoplasmic reticulum.
D) nuclear membrane.
E) nucleoplasm.
Answer: A
3) What would happen if the secondary messenger cGMP was
blocked in the de-etiolation pathway?
A) Specific protein kinase 1 would be activated, and
greening would occur.
B) Ca2+ channels would not open, and no greening would
occur.
C) Ca2+ channels could open, and specific protein kinase
2 could still be produced.
D) No transcription of genes that function in
de-etiolation would occur.
E) Transcription of de-etiolation genes in the nucleus
would not be affected.
Answer: C
4) If protein synthesis was blocked in etiolated cells,
what would be necessary for the "greening" of these cells?
A) reception of light by phytochrome
B) activation of protein kinase 1 by cAMP
C) activation of protein kinase 2 by Ca2+
D) post-translational modification of existing proteins
E) 100-fold decrease in cytosolic Ca2+ levels
Answer: D
5) The detector of light during de-etiolation (greening)
of a tomato plant is (are)
A) carotenoids.
B) xanthophylls.
C) phytochrome.
D) chlorophyll.
E) auxin.
Answer: C
6) Charles and Francis Darwin concluded from their
experiments on phototropism by grass seedlings that the part of the seedling
that detects the direction of light is the
A) tip of the coleoptile.
B) part of the coleoptile that bends during the response.
C) base of the coleoptile.
D) cotyledon.
E) phytochrome in the leaves.
Answer: A
7) Plants growing in a partially dark environment will
grow toward light in a response called phototropism. Which of the following
statements is true regarding phototropism?
A) It is caused by an electrical signal.
B) One chemical involved is ethylene.
C) Auxin causes a growth increase on one side of the
stem.
D) Auxin causes a decrease in growth on the side of the
stem exposed to light.
E) Removing the apical meristem enhances phototropism.
Answer: C
8) Which of the following conclusions is supported by the
research of both Went and Charles and Francis Darwin on shoot responses to
light?
A) When shoots are exposed to light, a chemical substance
migrates toward the light.
B) Agar contains a chemical substance that mimics a plant
hormone.
C) A chemical substance involved in shoot bending is
produced in shoot tips.
D) Once shoot tips have been cut, normal growth cannot be
induced.
E) Light stimulates the synthesis of a plant hormone that
responds to light.
Answer: C
9) We know from the experiments of the past that plants
bend toward light because
A) they need sunlight energy for photosynthesis.
B) the sun stimulates stem growth.
C) cell expansion is greater on the dark side of the
stem.
D) auxin is inactive on the dark side of the stem.
E) phytochrome stimulates florigen production.
Answer: C
10) Which of the following is a major mechanism whereby
hormones control plant development?
A) cell respiration via regulation of the citric acid
cycle
B) cell division via the cell cycle
C) cell elongation through production of cellulase
D) cell differentiation through altered spliceosome
activity
E) cell synthesis of proteins via altered gene expression
Answer: B
11) Evidence for phototropism due to the asymmetric
distribution of auxin moving down the stem
A) was first demonstrated in the coleoptiles of monocots.
B) has been found in all monocots and most eudicots.
C) has been shown to involve only IAA stimulation of cell
elongation on the dark side of the stem.
D) can be demonstrated with unilateral red light, but not
blue light.
E) is now thought by most plant scientists not to involve
the shoot tip.
Answer: A
12) According to modern ideas about phototropism in
plants,
A) light causes auxin to accumulate on the shaded side of
a plant stem.
B) auxin indirectly inhibits elongation of plant stem
cells.
C) auxin is produced by the apical meristem of the
coleoptile and moves downward.
D) all hormones move downward via the xylem.
E) cytokinins are more directly involved than auxins.
Answer: A
13) A plant seedling bends toward sunlight because
A) auxin migrates to the lower part of the stem due to
gravity.
B) there is more auxin on the light side of the stem.
C) auxin is destroyed more quickly on the dark side of
the stem.
D) auxin is found in greatest abundance on the dark side
of the stem.
E) gibberellins produced at the stem tip cause
phototropism.
Answer: D
14) The apical bud of a shoot produces ________,
resulting in the inhibition of lateral bud growth.
A) abscisic acid
B) ethylene
C) cytokinin
D) gibberellin
E) auxin
Answer: E
15) After some time, the tip of a plant that has been
forced into a horizontal position grows upward. This phenomenon is related to
A) calcium release from the endoplasmic reticulum of
shaded cells.
B) whether the plant is in the northern or southern
hemisphere.
C) gibberellin production by stems.
D) auxin production in cells receiving red light.
E) auxin movement toward the lower side of the stem.
Answer: E
16) Gravitropism in plant shoots and roots differ in that
A) only shoots depend upon auxin distribution.
B) only shoots depend upon the aggregation of statoliths.
C) only roots exhibit rapid elongation of specific cells.
D) only roots sense gravity at the tips.
E) the threshold and response time is much less in shoots
than in roots.
Answer: E
17) The ripening of fruit and the dropping of leaves and
fruit are principally controlled by
A) auxins.
B) cytokinins.
C) indole acetic acid.
D) ethylene.
E) carbon dioxide concentration (in air).
Answer: D
18) Which plant hormones would likely be found in high
amounts in a sprouting vegetative stem?
A) auxins, gibberellins, cytokinins
B) gibberellins, brassinosteroids, cytokinins
C) auxins, abscisic acid, ethylene
D) auxins, phytochrome, brassinosteroids
E) gibberellins, cytokinins, abscisic acid
Answer: A
19) Which of the following plant hormones would be found
in very low amounts in a mature, water-stressed tomato plant?
A) auxins, abscisic acid, brassinosteroids
B) auxins, gibberellins, cytokinins
C) gibberellins, cytokinins, ethylene
D) phytochrome, cytokinins, abscisic acid
E) brassinosteroids, ethylene, phytochrome
Answer: B
20) The plant hormone involved in aging and ripening of
fruit is
A) auxin.
B) ethylene.
C) florigen.
D) abscisic acid.
E) gibberellin.
Answer: B
21) When growing plants in culture, IAA is used to
stimulate cell enlargement. Which plant growth regulator has to now be added to
stimulate cell division?
A) ethylene
B) indoleacetic acid
C) gibberellin
D) cytokinin
E) abscisic acid
Answer: D
22) Why do coleoptiles grow toward light?
A) Auxin is destroyed by light.
B) Gibberellins are destroyed by light.
C) Auxin synthesis is stimulated in the dark.
D) Auxin moves away from the light to the shady side.
E) Gibberellins move away from the light to the shady
side.
Answer: D
23) Which of the following statements applies to plant
growth regulators?
A) They only act by altering gene expression.
B) They often have a multiplicity of effects.
C) They function independently of other hormones.
D) They directly control plant protein synthesis and
assembly.
E) They affect the division and elongation, but not the
differentiation, of cells.
Answer: B
24) Plant hormones produce their effects by
A) altering the expression of genes.
B) modifying the permeability of the plasma membrane.
C) modifying the structure of the nuclear envelope
membrane.
D) altering the expression of genes and modifying the
permeability of the plasma membrane.
E) modifying the permeability of the plasma membrane and
modifying the structure of the nuclear envelope membrane.
Answer: D
25) Why might animal hormones function differently than
plant hormones?
A) Animal receptors are very different than plant
receptors.
B) Plant cells have a cell wall that blocks passage of
many hormones.
C) Plants must have more precise timing of their
reproductive activities.
D) Plants are much more variable in their morphology and
development than animals.
E) Animal receptors are more hydrophobic than plant
receptors.
Answer: D
26) Which of the following hormones would never be found
in high concentrations in a dormant overwintering flower bud?
A) auxin
B) cytokinins
C) abscisic acid
D) ethylene
E) gibberellins
Answer: D
27) Plant hormones can have different effects at
different concentrations. This explains how
A) some plants are long-day plants and others are
short-day plants.
B) signal transduction pathways in plants are different
from those in animals.
C) plant genes recognize pathogen genes.
D) auxin can stimulate cell elongation in apical
meristems, yet will inhibit the growth of axillary buds.
E) gibberellin concentration can both induce and break
dormancy.
Answer: D
28) Auxins (IAA) in plants are known to affect all of the
following phenomena except
A) geotropism of shoots.
B) maintenance of dormancy.
C) phototropism of shoots.
D) inhibition of lateral buds.
E) fruit development.
Answer: B
29) How does indoleacetic acid affect fruit development?
A) by preventing pollination
B) by inhibiting formation of the ovule
C) by promoting gene expression in cambial tissue
D) by promoting rapid growth of the ovary
E) by inducing the formation of brassinosteroids
Answer: D
30) Oat seedlings are sometimes used to study auxins
because
A) they are a readily accessible monocot, and auxins
affect only monocots.
B) they have a stiff coleoptile.
C) they green rapidly in the light.
D) their coleoptile exhibits a strong positive
phototropism.
E) monocots inactivate synthetic auxins.
Answer: D
31) Auxin triggers the acidification of cell walls, which
results in rapid growth, but also stimulates sustained, long-term cell
elongation. What best explains how auxin brings about this dual growth
response?
A) Auxin binds to different receptors in different cells.
B) Different concentrations of auxin have different
effects.
C) Auxin causes second messengers to activate both proton
pumps on the plasma membrane and certain genes within the same cells.
D) The dual effects are due to two different types of
auxins that are produced by different genes.
E) Other antagonistic hormones modify auxin's effects.
Answer: C
32) If a farmer wanted more loosely packed clusters of
grapes, he would most likely spray the immature bunches with
A) auxin.
B) gibberellins.
C) cytokinins.
D) abscisic acid.
E) ethylene.
Answer: B
33) Which of the following plant hormones are most likely
to act synergistically if expressed or applied to a drought-stricken plant?
A) auxin and ethylene
B) phytochrome and gibberellins
C) gibberellins and abscisic acid
D) abscisic acid and ethylene
E) brassinosteroids and cytokinins
Answer: D
34) Which of the following statements best summarizes the
acid growth hypothesis in an actively growing shoot?
A) Auxin stimulates proton pumps in the plasma membrane
and tonoplast.
B) Auxin-activated proton pumps lower the pH of the cell
wall, which breaks bonds and makes the walls more flexible
C) Auxins and gibberellins together act as a lubricant to
help stretch cellulose microfibrils.
D) Auxins activate aquaporins that increase turgor
pressure in the cells.
E) Auxins and gibberellins are transported to the
vacuoles to build up turgor pressure.
Answer: B
35) According to the acid growth hypothesis, auxin works
by
A) dissolving sieve plates, permitting more rapid
transport of nutrients.
B) dissolving the cell membranes temporarily, permitting
cells that were on the verge of dividing to divide more rapidly.
C) changing the pH within the cell, which would permit
the electron transport chain to operate more efficiently.
D) increasing wall plasticity and allowing the affected
cell walls to elongate.
E) greatly increasing the rate of deposition of cell wall
material.
Answer: D
36) Which of the following hormones would be most useful
in promoting the rooting of plant cuttings?
A) oligosaccharins
B) abscisic acid
C) cytokinins
D) gibberellins
E) auxins
Answer: E
37) Which of the following plant hormones would most
likely be found in high concentrations in a mature, slightly overripe fruit?
A) auxins and cytokinins
B) auxins and abscisic acid
C) gibberellins and cytokinins
D) cytokinins and ethylene
E) abscisic acid and ethylene
Answer: E
38) The aleurone layer is stimulated to release ________
and ________ as a result of giberrellin release from the embryo.
A) proteins; amino acids
B) carbohydrates; sugars
C) auxins; cytokinins
D) amylase; protease
E) RNAase; DNAase
Answer: D
39) Which of the following field treatments would be most
likely to result in a wheat or corn field with most of the plants of uniform
height?
A) auxin spray early in the season
B) gibberellin spray early in the season
C) abscisic acid spray late in the season
D) auxin spray late in the season
E) auxin and gibberellin spray late in the season
Answer: C
40) If you were shipping green bananas to a supermarket
thousands of miles away, which of the following chemicals would you want to
eliminate from the plants' environment?
A) CO₂
B) cytokinins
C) ethylene
D) auxin
E) gibberellic acids
Answer: C
41) Which of the following is currently the most powerful
method of research on plant hormones?
A) comparing photoperiodic responses
B) comparing tropisms with turgor movements
C) subjecting plants to various abiotic stresses
D) studying plant/animal interactions
E) analyzing mutant plants
Answer: E
42) We tend to think of plants as immobile when, in fact,
they can move in many ways. Which of the following is a legitimate way in which
plants move?
A) stretching or shrinking movements up or down in
response to light
B) folding and unfolding of leaves using muscle-like
tissues
C) growth movements toward or away from light
D) cessation of plant growth in response to wind or touch
E) rapid responses using action potentials from nervous
tissue cells similar to those found in the nervous tissue of animals
Answer: C
43) Which of the following plant growth responses is
primarily due to the action of auxins?
A) leaf abscission
B) fruit development
C) cell division
D) the detection of photoperiod
E) cell elongation
Answer: E
44) Experiments on the positive phototropic response of
plants indicate that
A) light destroys auxin.
B) auxin moves down the plant apoplastically.
C) auxin is synthesized in the area where the stem bends.
D) auxin can move to the shady side of the stem.
E) auxin is only of secondary importance in the process.
Answer: D
45) Why are lateral buds often inhibited from sprouting
even though a stem may be actively elongating?
A) The cells of lateral buds are more sensitive to auxin
than stem cells.
B) Lateral buds are high in abscisic acid that prevents
elongation.
C) Lateral buds are low in gibberellins.
D) Stem cells lack receptors for auxin.
E) Stem cells can overcome auxin inhibition with high
levels of gibberellins.
Answer: A
46) The synthesis of which of the following hormones
would be a logical first choice in an attempt to produce normal growth in
mutant dwarf plants?
A) indoleacetic acid
B) cytokinin
C) gibberellin
D) abscisic acid
E) ethylene
Answer: C
47) Incandescent light bulbs, which have high output of
red light, are least effective in promoting
A) photosynthesis.
B) seed germination.
C) phototropism.
D) flowering.
E) entrainment of circadian rhythms.
Answer: C
48) Both red and blue light are involved in
A) stem elongation.
B) photoperiodism.
C) positive phototropism.
D) tracking seasons.
E) all of the above.
Answer: A
49) Seed packets give a recommended planting depth for
the enclosed seeds. The most likely reason some seeds are to be covered with
only 1/4 inch of soil is that the
A) seedlings do not produce a hypocotyl.
B) seedlings do not have an etiolation response.
C) seeds require light to germinate.
D) seeds require a higher temperature to germinate.
E) seeds are very sensitive to waterlogging.
Answer: C
50) A short-day plant will flower only when
A) days are shorter than nights.
B) days are shorter than a certain critical value.
C) nights are shorter than a certain critical value.
D) nights are longer than a certain critical value.
E) days and nights are of equal length.
Answer: D
51) A flash of red light followed by a flash of far-red
light given during the middle of the night to a short-day plant will likely
A) cause increased flower production.
B) have no effect upon flowering.
C) inhibit flowering.
D) stimulate flowering.
E) convert florigen to the active form.
Answer: B
52) Many plants flower in response to day-length cues.
Which of the following statements best summarizes this phenomenon?
A) As a rule, short-day plants flower in the summer.
B) As a rule, long-day plants flower in the spring or
fall.
C) Long-day plants flower in response to long days, not
short nights.
D) Flowering in day-neutral plants is only influenced by
day length if there is an exceptionally warm spring.
E) Flowering in short-day and long-day plants is
controlled by phytochrome.
Answer: E
53) Which of the following treatments would enhance the
level of the Pfr form of phytochrome?
A) exposure to far-red light
B) exposure to red light
C) long dark period
D) inhibition of protein synthesis
E) synthesis of phosphorylating enzymes
Answer: B
54) Most plants close their stomata at night. What color
of light would be most effective in promoting stomatal opening in the middle of
the night?
A) red
B) far-red
C) blue
D) red followed by far-red
E) far-red followed by blue
Answer: C
55) The houseplants in a windowless room with only
fluorescent lights begin to grow tall and leggy. Which of the following
treatments would promote more normal growth?
A) Leave the lights on at night as well as during the
day.
B) Add additional fluorescent tubes to increase the light
output.
C) Add some incandescent bulbs to increase the amount of
red light.
D) Set a timer to turn on the lights for 5 minutes during
the night.
E) Turn off the lights for 5 minutes during the day.
Answer: C
56) In legumes, it has been shown that "sleep"
(nastic) movements are correlated with
A) positive thigmotropisms.
B) rhythmic opening and closing of K+ channels in motor
cell membranes.
C) senescence (the aging process in plants).
D) flowering and fruit development.
E) ABA-stimulated closing of guard cells caused by loss
of K+.
Answer: B
57) Which of the following statements is correct with
regards to a "circadian rhythm" in plants?
A) It may have the same signal transduction pathway in
all organisms.
B) Once set, it cannot be changed.
C) It works independently of photoperiodic responses.
D) Once set, it is independent of external signals.
E) It can be changed to a longer or shorter period by
altering the light quality.
Answer: A
58) The biological clock controlling circadian rhythms
must ultimately
A) depend on environmental cues.
B) affect gene transcription.
C) stabilize on a 24-hour cycle.
D) speed up or slow down with increasing or decreasing
temperature.
E) do all of the above.
Answer: B
59) Plants often use changes in day length (photoperiod)
to trigger events such as dormancy and flowering. It is logical that plants
have evolved this mechanism because photoperiod changes
A) are more predictable than air temperature changes.
B) alter the amount of energy available to the plant.
C) are modified by soil temperature changes.
D) can reset the biological clock.
E) are correlated with moisture availability.
Answer: A
60) If the range of a species of plants expands to a
higher latitude, which of the following processes is the most likely to be
modified by natural selection?
A) circadian rhythm
B) photoperiodic response
C) phototropic response
D) biological clock
E) thigmomorphogenesis
Answer: B
61) What does a short-day plant require in order to
flower?
A) a burst of red light in the middle of the night
B) a burst of far-red light in the middle of the night
C) a day that is longer than a certain length
D) a night that is longer than a certain length
E) a higher ratio of Pr to Pfr
Answer: D
62) If a short-day plant has a critical night length of
15 hours, then which of the following 24-hour cycles will prevent flowering?
A) 8 hours light/16 hours dark
B) 4 hours light/20 hours dark
C) 6 hours light/2 hours dark/light flash/16 hours dark
D) 8 hours light/8 hours dark/light flash/8 hours dark
E) 2 hours light/20 hours dark/2 hours light
Answer: D
63) A long-day plant will flower if
A) the duration of continuous light exceeds a critical
length.
B) the duration of continuous light is less than a
critical length.
C) the duration of continuous darkness exceeds a critical
length.
D) the duration of continuous darkness is less than a
critical length.
E) it is kept in continuous far-red light.
Answer: D
64) Plants that have their flowering inhibited by being
exposed to bright lights at night are
A) day-neutral plants.
B) short-night plants.
C) devoid of phytochrome.
D) short-day plants.
E) long-day plants.
Answer: D
65) Classic experiments suggested that a floral stimulus,
florigen, could move across a graft from an induced plant to a noninduced plant
and trigger flowering. Recent evidence using Arabidopsis has recently shown
that florigen is probably
A) a phytochrome molecule that is activated by red light.
B) a protein that is synthesized in leaves, travels to
the shoot apical meristems, and initiates flowering.
C) a membrane signal that travels through the symplast
from leaves to buds.
D) a second messenger that induces Ca++ ions to change
membrane potential.
E) a transcription factor that controls the activation of
florigen-specific genes.
Answer: B
66) A short-day plant exposed to nights longer than the
minimum for flowering but interrupted by short flashes of light
A) never flower.
B) might flower depending upon the duration of the light
flash.
C) will not be affected and will flower.
D) might flower depending upon the wavelengths of the
light flashes.
E) will still flower if ethylene is administered.
Answer: D
67) A long-day plant will flower
A) in the late fall.
B) when the night is shorter than a critical value.
C) only under artificial light in the summer.
D) during short days with proper fertilization.
E) regardless of the photoperiod imposed.
Answer: B
68) What do the results of research on gravitropic
responses of roots and stems show?
A) Different tissues have the same response to auxin.
B) The effect of a plant hormone can depend on the
tissue.
C) Some responses of plants require no hormones at all.
D) Light is required for the gravitropic response.
E) Cytokinin can only function in the presence of auxin.
Answer: B
69) Which of the following best describes positive
gravitropism exhibited by plant roots?
A) It is mediated by auxin similar to the phototropism
responses in shoots.
B) It depends on an inhibition of elongation of some
cells.
C) Gravity causes gibberellins to accumulate on the lower
side of roots.
D) The phenomenon depends upon inhibition of cell
elongation of certain root cells by abscisic acid.
E) All of the above are correct.
Answer: A
70) Vines in tropical rain forests must grow toward large
trees before being able to grow toward the sun. To reach a large tree, the most
useful kind of growth movement for a tropical vine presumably would be the
opposite of
A) positive thigmotropism.
B) positive phototropism.
C) positive gravitropism.
D) sleep movements.
E) circadian rhythms.
Answer: B
71) A botanist discovers a plant that lacks the ability
to form starch grains in root cells, yet the roots still grow downward. This
evidence refutes the long-standing hypothesis that
A) falling statoliths trigger gravitropism.
B) starch accumulation triggers the negative phototropic
response of roots.
C) starch grains block the acid growth response in roots.
D) starch is converted to auxin, which causes the
downward bending in roots.
E) starch and downward movement are necessary for
thigmotropism.
Answer: A
72) Which of the following watering regimens will be most
effective at keeping a lawn green during the hot, dry summer months?
A) daily sprinkling to soak the soil to 0.5 inch
B) sprinkling every other day to soak the soil to 1.0
inch
C) sprinkling every third day to soak the soil to 2.0
inches
D) daily sprinkling to soak the soil to 0.5 inch or
sprinkling every other day to soak the soil to 1.0 inch
E) sprinkling every other day to soak the soil to 1.0
inch or sprinkling every third day to soak the soil to 2.0 inches
Answer: C
73) You are part of a desert plant research team trying
to discover crops that will be productive in arid climates. You discover a
plant that produces a hormone under water-deficit conditions that triggers a
suite of drought responses. Most likely the hormone is
A) ABA.
B) GA.
C) IAA.
D) 2, 4-D.
E) salicylic acid.
Answer: A
74) If you wanted to genetically engineer a plant to be
more resistant to drought, increasing amounts of which of the following
hormones might be a good first attempt?
A) abscisic acid
B) brassinosteroids
C) gibberellins
D) cytokinins
E) auxin
Answer: A
75) Plant cells begin synthesizing large quantities of
heat-shock proteins
A) after the induction of chaperone proteins.
B) in response to the lack of CO₂ following the closing
of stomata by ethylene.
C) when desert plants are quickly removed from high
temperatures.
D) when they are subjected to moist heat (steam) followed
by electric shock.
E) whenever the external temperature exceeds the
threshold where photosynthesis is negatively impacted.
Answer: E
76) Most scientists agree that global warming is
underway; thus, it is important to know how plants respond to heat stress.
Which of the following would be a useful line of inquiry to try and improve
plant response and survival to heat stress?
A) the production of heat-stable carbohydrates
B) increased production of heat-shock proteins
C) the opening of stomata to increase evaporational heat
loss
D) protoplast fusion experiments with xerophytic plants
E) all of the above
Answer: B
77) In extremely cold regions, woody species may survive
freezing temperatures by
A) emptying water from the vacuoles to prevent freezing.
B) decreasing the numbers of phospholipids in cell
membranes.
C) decreasing the fluidity of all cellular membranes.
D) producing canavanine as a natural antifreeze.
E) increasing cytoplasmic levels of specific solute
concentrations, such as sugars.
Answer: E
78) Which of the following is a likely response of plants
to cold stress?
A) the production of a specific solute "plant
coagulant " that reduces water loss
B) reducing the size of ice crystals
C) conversion of the fluid mosaic cell membrane to a
solid mosaic one
D) an increase in sterol concentration of membrane lipids
so that the membranes remain flexible
E) increasing the proportion of unsaturated fatty acids
in the membranes
Answer: C
79) Bald cypress and loblolly pine are both gymnosperm
trees native to the southern United States. The cypress grows in swamps; the
pine grows in sandy soil. How do you think their anatomies differ?
A) There are larger intercellular spaces in the roots of
the cypress than in the roots of the pine.
B) Water-conducting cells are larger in the stems of the
cypress than in the stems of the pine.
C) The springwood and summerwood are more distinct in the
cypress.
D) There is less parenchyma in the roots of the cypress
than in the pine roots.
E) There are no major anatomical differences between
these species because they're both gymnosperms.
Answer: A
80) The initial response of the root cells of a tomato
plant watered with seawater would be to
A) rapidly produce organic solutes in the cytoplasm.
B) rapidly expand until the cells burst.
C) begin to plasmolyze as water is lost.
D) actively transport water from the cytoplasm into the
vacuole.
E) actively absorb salts from the seawater.
Answer: C
81) Which of the following best explains both the growth
of a vine up the trunk of a tree as well as the directional growth of a
houseplant toward a window?
A) nastic movement
B) taxic movement
C) tropism response
D) morphological response
E) acclimation
Answer: C
82) The rapid leaf movements resulting from a response to
touch (thigmotropism) primarily involve
A) rapid growth response.
B) potassium channels.
C) nervous tissue.
D) aquaporins.
E) stress proteins.
Answer: B
83) Which of the following is the most likely plant
response to an attack by herbivores?
A) leaf abscission to prevent further loss
B) early flowering to try and reproduce before being
eaten
C) production of chemical compounds for defense or to
attract predators
D) production of physical defenses, such as thorns
E) production of thicker bark and cuticle to make it more
difficult to eat
Answer: D
84) In order for a plant to initiate chemical responses
to herbivory,
A) the plant must be directly attacked by an herbivore.
B) volatile "signal" compounds must be
perceived.
C) gene-for-gene recognition must occur.
D) phytoalexins must be released.
E) it must be past a certain developmental age.
Answer: B
85) Plants are affected by an array of pathogens. Which
of the following is a likely plant defense/response against disease?
A) cells near the point of infection destroying
themselves to prevent the spread of the infection
B) production of chemicals that repel pathogens
C) transcriptional level recognition followed by
production of stress proteins
D) thickening the cuticle so that pathogens have trouble
penetrating the tissues
E) stopping all xylem and phloem movement within infected
tissues
Answer: A
86) A pathogenic fungus invades a plant. What does the
infected plant produce in response to the attack?
A) antisense RNA
B) phytoalexins
C) phytochrome
D) statoliths
E) thickened cellulose microfibrils in the cell wall
Answer: B
87) Which of the following would be the most effective
way to prevent herbivory in a non-woody plant?
A) production of the amino acid analog canavanine
B) release of insect pheromones
C) production of foul-tasting compounds
D) thickened cuticle
E) enhanced levels of salicylic acid
Answer: D
88) The transduction pathway that activates systemic
acquired resistance in plants is initially signaled by
A) antisense RNA.
B) Pfr phytochrome.
C) salicylic acid.
D) abscisic acid.
E) red, but not far-red, light.
Answer: C
89) Which of the following would only be activated or
upregulated after a plant has already been infected by a pathogen?
A) phytochrome
B) salicylic acid
C) molecular chaperones
D) stress proteins
E) brassinosteroids
Answer: B
90) A plant will recognize a pathogenic invader
A) if it has many specific plant disease resistance (R)
genes.
B) when the pathogen has an R gene complementary to the
plant's antivirulence (Avr) gene.
C) only if the pathogen and the plant have the same R
genes.
D) if it has the specific R gene that corresponds to the
pathogen molecule encoded by an Avr gene.
E) when the pathogen secretes Avr protein.
Answer: D
91) What is the probable role of salicylic acid in the
defense responses of plants?
A) to destroy pathogens directly
B) to activate systemic acquired resistance of plants
C) to close stomata, thus preventing the entry of
pathogens
D) to activate heat-shock proteins
E) to sacrifice infected tissues by hydrolyzing cells
Answer: B
92) When an arborist prunes a limb off a valuable tree,
he or she usually paints the cut surface. The primary purpose of the paint is
to
A) minimize water loss by evaporation from the cut
surface.
B) improve the appearance of the cut surface.
C) stimulate growth of the cork cambium to
"heal" the wound.
D) block entry of pathogens through the wound.
E) induce the production of phytoalexins.
Answer: D
93) Plant hormonal control differs from animal hormonal
control in that
A) there are no separate hormone-producing organs in
plants as there are in animals.
B) all production of hormones is local in plants with
little long-distance transport.
C) plants do not exhibit feedback mechanisms like
animals.
D) only animal hormone concentrations are developmentally
regulated.
E) only animal hormones may have either external or
internal receptors.
Answer: A
94) Unlike animal hormones, plant hormones are mainly
A) hydrophobic molecules.
B) products of stresses in the environment.
C) small, easily transportable molecules.
D) unable to cross membranes.
E) direct products of photosynthesis.
Answer: C
95) In cases where plants exhibit generalized defense
responses in organs distant from the infection site, this is termed
A) hyperactive responses.
B) systemic acquired resistance.
C) pleiotropy.
D) hyperplasia.
E) general systemic response.
Answer: B
96) The heavy line in Figure illustrates the
relationship between auxin concentration and cell growth
in stem tissues.
If the same range of concentrations were
applied to lateral buds, what curve(s) would probably be produced?
A) I
B) II
C) III
D) II or III
E) I or III
Answer: A
97) The results of this experiment, shown on the left of
the graph (area A), may be used to
A) show that these plants can live without gibberellin.
B) show that gibberellin is necessary in positive
gravitropism.
C) show that taller plants with more gibberellin produce
fruit (pods).
D) show a correlation between plant height and
gibberellin concentration.
E) study phytoalexins in plants.
Answer: D
98) This experiment suggests that the unknown amount of
gibberellin in the experimental plant (B) is approximately
A) zero.
B) 0.01 μg/mL.
C) 0.1 μg/mL.
D) 1.0 μg/mL.
E) equal to the amount of gibberellin in the shortest
plant.
Answer: C
99) In nature, poinsettias bloom in early March. Research
has shown that the flowering process is triggered three months before blooming
occurs. In order to make poinsettias bloom in December, florists change the
length of the light-dark cycle in September. Given the information and clues
above, which of the following is a correct statement about poinsettias?
A) They are short-day plants.
B) They require a light period longer than some set
minimum.
C) They require a shorter dark period than is available
in September.
D) The dark period can be interrupted without affecting
flowering.
E) They will flower even if there are brief periods of
far-red illumination during the nighttime.
Answer: A
100) A botanist exposed two groups of the same plant
species to two photoperiods–one with 14 hours of light and 10 hours of dark and
the other with 10 hours of light and 14 hours of dark. Under the first set of
conditions, the plants flowered, but they failed to flower under the second set
of conditions. Which of the following conclusions would be consistent with
these results?
A) The critical night length is 14 hours.
B) The plants are short-day plants.
C) The critical day length is 10 hours.
D) The plants can convert phytochrome to florigen.
E) The plants flower in the late spring.
Answer: E
101) The hormone that helps plants respond to drought is
A) auxin.
B) gibberellin.
C) cytokinin.
D) ethylene.
E) abscisic acid.
Answer: E
102) Auxin enhances cell elongation in all of the these
ways except
A) increased uptake of solutes.
B) gene activation.
C) acid-induced denaturation of cell wall proteins.
D) increased activity of plasma membrane proton pumps.
E) cell wall loosening.
Answer: C
103) Charles and Francis Darwin discovered that
A) auxin is responsible for phototropic curvature.
B) auxin can pass through agar.
C) light destroys auxin.
D) light is perceived by the tips of coleoptiles.
E) red light is most effective in shoot phototropism.
Answer: D
104) How may a plant respond to severe heat stress?
A) by reorienting leaves to increase evaporative cooling
B) by creating air tubes for ventilation
C) by initiating a systemic acquired resistance response
D) by increasing the proportion of unsaturated fatty
acids in cell membranes, reducing their fluidity
E) by producing heat-shock proteins, which may protect
the plant's proteins from denaturing
Answer: E
105) The signaling molecule for flowering might be
released earlier than usual in a long-day plant exposed to flashes of
A) far-red light during the night.
B) red light during the night.
C) red light followed by far-red light during the night.
D) far-red light during the day.
E) red light during the day.
Answer: B
106) If a long-day plant has a critical night length of 9
hours, which 24-hour cycle would prevent flowering?
A) 16 hours light/8 hours dark
B) 14 hours light/10 hours dark
C) 15.5 hours light/8.5 hours dark
D) 4 hours light/8 hours dark/4 hours light/8 hours dark
E) 8 hours light/8 hours dark/light flash/8 hours dark
Answer: B
107) A plant mutant that shows normal gravitropic bending
but does not store starch in its plastids would require a reevaluation of the
role of ________ in gravitropism.
A) auxin
B) calcium
C) statoliths
D) light
E) differential growth
Answer: C
108) Which type of mutant would be most likely to produce
a bushier phenotype?
A) auxin overproducer
B) strigolactone overproducer
C) cytokinin underproducer
D) gibberellin overproducer
E) strigolactone underproducer
Answer: E
TRYAGAIN
No
|
Macam gerak
|
Artinya
|
Contohnya
|
1
|
TIGMONASTI
(SEISMONASTI)
|
Gerak nasti yang rangsangannya adalahsentuhan
|
Gerak menutupnya daun putri malu (Mimosa pudica)
karena sentuhan
|
Gerak tumbuhan venus menangkap serangga
|
|||
2
|
NIKTINASTI
|
Gerak nasti yang rangsangannya adalah suasana
gelap (sore/malam)
|
Gerak menutupnya daun-daun majemuk tumbuh-tumbuhan
polong-polongan , seperti, lamtoro, kembang merak. Juga tumbuhan blimbing
|
3
|
FOTONASTI
|
Gerak nasti yang rangsangannya adalah cahaya
|
Gerak membuka dan menutupnya bunga pukul empat
(Mirabilis jalapa)
|
4
|
NASTI
KOMPLEKS
|
Gerak nasti yang disebabkan oleh factor-faktor cahaya,
suhu, zat kimia dan air
|
Gerak membuka dan menutupnya stomata
|
5
|
TERMONASTI
|
Gerak nasti yang disebabkan oleh
rangsangan suhu
|
Mekarnya bunga tulip di musim semi
|
6
|
FOTOTROPISME
|
Gerak tropisme yang disebabkan rangsangancahaya
|
· Gerak
tumbuh ujung batang ke arah cahaya
· Gerak
bunga matahari ke arah cahaya matahari.
|
7
|
GEOTROPISME
|
Gerak tropisme yang disebabkanRangsangan gaya tarik
bumi(Gravitasi)
|
· Gerak
tumbuh ujung akar ke pusat bumi(geotropism positif)
· Gerak
akar napas tumbuhan bakau(geotropisme negative)
|
8
|
TIGMOTROPISME
|
Gerak tropisme yang disebabkan rangsangansentuhan sehingga
sulur (bagian tumbuhan) membelit/ melilit
|
Gerak membelit atau melilitnya sulur (tanaman
anggur atau tanaman ketimun)tumbuhan pada batang kayu di dekatnya
|
9
|
HIDROTROPISME
|
Gerak tropisme yang disebabkan rangsanganair
|
Gerak tumbuh ujung akarmenuju ke
tempat yang basah
|
10
|
KEMOTROPISME
|
Gerak tropisme yang disebabkan rangsanganzat kimia
|
· Gerak
ujung akar menuju zat makanan (kemotropisme positif)
· Gerak
ujung akar menjauhi racun(kemotropisme negative)
|
11
|
FOTOTAKSIS
|
Gerak taksis yang dipengaruhi oleh rangsangan cahaya
|
· Gerak
kloroplas menuju sisi sel yang terkena cahaya
· Gerak
ganggang hijau(Euglena) kearah cahaya
|
12
|
KEMOTAKSIS
|
Gerak taksis yang dipengaruhi oleh rangsangan zat
kimia
|
Gerak sel sperma menuju pada sel telur karena ovum
mengeluarkan zat kimia pada peristiwa pembuahan (fertilisasi), pada tumbuhan
lumut dan tumbuhan paku.
|
TRYAGAIN
1. A tropism:
A is the loss of water through the leaves of a plant
B is the wilting that occurs when a plant receives
insufficient water
C occurs when a plant grows in response to a stimulus
such as light
2. A plant tropism where the plant responds towards a
stimulus is:
A unreliable
B negative
C positive
3. The growth of plant roots towards the earth is:
A geotropism
B gravitropism
C both of the above
4. Auxins responsible for phototropism are produced in
the shoot tip called the:
A xylem
B root hairs
C coleoptile
5. The response of certain plants to touch is:
A geotropism
B thigmotropism
C phototropism
6. A plant which may flower and fruit naturally all year
round is the:
A chrysanthemum
B tomato
C poinsettia
7. The dropping of leaves and fruit is known as:
A autumn growth
B abscission
C fall
8. Pruning a plant causes it to:
A grow more branches
B become bushier
C both of the above
9. The flowering response is called:
Aphototropism
Bphotoperiodism
Capical dominance
10. Elongation of cells is produced by hormones called:
Agibberellins
Bauxins
Cboth of the above
11. The hormone that plays a major role in leaf loss of
deciduous trees is:
Afallic acid
Babscisic acid
Cautumnal hormone
12. Auxins cause a plant to bend towards light because:
Athey are lost through photosynthesis as more light
strikes the plant
Bthey increase in amount on the lit side of the plant to
lengthen the cells
Cthey concentrate in the dark side of cells to elongate
those cells
13. What causes apical dominance?
APruning the ends of tree branches
BShortened side branches occur when there are more auxins
in the tips of branches at the top of trees
CNatural occurrence cause by gibberellins
14. What gas is used to encourage unripe bananas to
ripen?
Aoxygen
Bcarbon monoxide
Cethylene
15. What causes many flowering plants to flower?
Achanging fertiliser quantities in winter
Bincreasing hours of light in summer
Cchanging duration of darkness each day
